Combustion apparatus



Patented Nov. 21, 1935 UNITED STATES PATENT OFFICE Motor WheelCorporation, corporation of Michigan Lansing, Mich., a

Application January 2, 1937, Serial No. 118,867

2 Claims.

15 Fig. 2 is a sectional view taken on substantially the line 2-2 ofFig. 1;

Fig. 3 is an enlarged vertical sectional view of the burner forming apart of the heater shown in Fig. l; 20 Fig. 4 is a fragmentary planviewof the bailie ring forming a part of the burner; and

Fig. 5 is an enlarged fragmentary sectional view of the burnerillustrating an alternative method of attaching the bailie ring to theburner. 5 The heater shown in Fig. 1 includes an outer casing lsurrounding a burner H. The details of the burner are shown in Fig. 3.It consists of a generally--frusto-conical pressed metal side wall l2 ofsubstantially uniformly increasing 30 diameter from its bottom to itstop. A pan like bottom wall I3 is secured to the lower extremity .of theshell in a manner to form a fluid tight joint therewith, as by welding.

Adjacent its upper extremity, the shell I2 is 35 provided with aradially inwardly extending annular rib l4. Above the rib M, the shellis provided with a radially outwardly extending rib I5. The rib l4serves to support a centrally apertured top wall I6. The rib I5 isutilized in 40 securing the burner in the casing and also serves a tosecure a bafiie IT in position.

Baflie I! is a centrally apertured disk made up of two separate sectionsIla and llb which are secured to each other by cotter keys l8. The 45bafiie is provided with depending legs I!) adapted to rest upon the topwall It and to space the bafiie therefrom. The radially outer edge ofeach of the legs I9 is formed with a projection 19a adapted to beinserted in the rib IE, to lock the 50 battle in position. I

In installing the baliie ll, the separate sections are inserted withinthe burner and then moved radially outwardly so that the leg portionsI90. extend into the rib I5. With the sections 11a and 55 Hb in thisposition the cotter pins 18 may be dary air inlet openings.

.fianged radially inwardly as indicated at l2a.

The sections Ila and Nb of the bafiie are installed separately and afterthe reduced peripheral portions lie of the baflie sections have beeninserted under the flange He, the cotter keys l8 may be installed andthe bafile is securely locked in place. '15

The tapered side wall l2 of the burner is provided with a plurality ofprimary and secondary air inlet openings 20 and 2|, respectively. Theprimary air inlet openings 20 are located beneath top wall It and thesecondary air inlet openings 20 2! are located above the top wall l6 andbelow the baflie ll, being formed in the lower portion of rib l5 so thatair enters therethrough in a direction toward bafile ll. The size andspacing of these air inlet openings are important. Within reasonablevariations, it is essential that the primary air inlet openings 20 be ofrelatively small cross sectional area and spaced substantlallyuniformly, both vertically and horizontally. Secondary air inletopenings 2| should also be 0 spaced uniformly and are preferably fewerinv number but relatively larger than the primary openings 20. It isessential, for best results, that-the size and spacing of all of the airinlet openings be such that the total cross sectional area of theprimary air inlet openings is substantially greater than the total crosssectional area of the secondary air inlet openings. In

other words, best results are obtained in the operation of the burner ifa greater volume of air is introduced into the burner through theprimary air inlet openings than through the secon- In the burner shownthe side wall I2 is approximately 7% inches high and varies from adiameter of approximately 10 inches at the bottom to a diameter ofapproximately 12 inches at the top. There-are 26 holes in each row ofprimary air inlet openings 2|], spaced as shown. These holes. are all ofthe same size except the top row, which are slightly larger than theothers. The total area of the primary air inlet openings isapproximately .8 square inch. There are 52 holes in the single row ofsecondary air inlet openings spaced as shown. The total area of the 55secondary air inlet openings is approximately .5 square inch.

The size of the central openings in the top l6 and the baflle II arealso of substantial impor- 5 tance in the burner shown, the diameter ofthe opening in the top wall I6 is approximately 6 inches and thediameter of the opening in baflle I1 is approximately 9 inches.

The burner side wall I2 is preferably formed 10 from-a strip ofrelatively light gauge sheet metal. The holes 20 and 2| may be punchedor drilled in the metal while it is in strip form and the stripafterwards coiled to the shape shown. The ribs l4 and I5 are preferablyformed after the strip has been coiled and permanently secured in itsflnal shape. The bottom wall 13, the top wall l6, and the baflle I! areall preferably formed of cast iron, although the bottom wall may beformed of relatively heavy gauge steel if desired.

The burner II is secured to casing III as shown in Fig. 1. The casing isprovided with a radially inwardly extending rib 22 intermediate itsextremities. The burner is arranged within the casing with the radiallyoutwardly extending rib I5 of the former contacting the rib 22 of thecasing. The burner is secured in this position by a screw threadeddevice 23 mounted in a bracket 24 extending across the bottom of easingl0. Suitable sealing means, such as asbestos or the like, is placedbetween the cooperating ribs l5 and 22 to provide an air tight jointtherebetween.

Bracket 24 does not completely close the bottom of casing Ill and issecured in position by the same securing elements 25 which secure thesupporting legs. 26 to the lower extremities of the casing l0. 7

The lower portion of casing I0 is open to the atmosphere and forms anair compartment 21 surrounding burner II. The upper portion of thecasing l0, above burner ll, serves as a combustion chamber 28. A topwall 29 is provided for the upper extremity of easing I0. Combustionchamber 28 is connected with a chimney 30 by an exhaust pipe 3|. Pipe 3|is provided with a draft regulator 3la. Casing I0 is provided with adoor 32 in its upper part which provides access to the interior of thecombustion chamber 28.

By reason of the tapered or frusto-conical form of burner II it ispossible to use a single cylindrical casing ill of substantially uniformdiameter, as a combustion chamber and an air compartment for the burner.As shown, the diameter of the casing is substantially no greater thanthe maximum (top) diameter of burner H. The air compartment 21constitutes the annular space between the side wall of the burner II andthat portion of casing Ill below the rib 22 formed therein.

Oil is delivered to the lower portion of burner H from a source ofsupply, not shown, through a supply pipe, 33. A conventional form ofregulating valve shown diagrammatically at 34 in Fig. 1 is associatedwith pipe 33. Air is drawn into the burner ll through the openings 20and 2| by means of the draft produced by chimney 30. For this purpose itis necessary that air compartment 21 be-open to the atmosphere. Byreason of the air tight joint between ribs 15 and 22, the only air whichis introduced into the apparatus enters the apparatus through air inletopenings 20 and 2i.

A characteristic and valuable feature inherent in the present apparatusis its capacity to burn varying amounts of oil and thereby produce a Itis well known in the art to which this invention relates that it isdesirable to avoid a concentration of air at any point in the apparatus.It is also well known that adequate provision must be made to preventexplosions which would result if the combustion flame becameextinguished when the apparatus is full of combustible oil vapors.

Heretofore, it has been the'practice to provide against this explosionhazard by introducing a substantially excessive amount of secondary airin order to maintain fire in the apparatus regardless of any excess offuel vapors that might be generated. So far as applicant is aware, hewas the first to discover that such an excessive amount of secondary airis not necessary to overcome this explosion hazard providing a properform of apparatus is employed. The present invention eliminates thenecessity of employing an undesirable amount of excess secondary air inorder to attain the necessary insurance against explosions.

As previously stated, the volume of secondary air introduced into theapparatus disclosed in this application is substantially less than thevolume of primary air utilized. This makes for more efiicient operationthan where a greater amount of secondary air is used.

Unlike the prior art devices, applicant directs the secondary airtoward, and in part at least against, the baflle ring l9. Consequently,the velocity of the secondary air is substantially decreased. At thesame time the secondary air is directed toward the central opening intop wall l6 through which the oil vapors flow. Thus, there is alwayspresent adjacent this opening a relatively large volume of relativelyslow moving air which contacts the relatively fast moving oil vaporsarising from the burner.

The diiference in velocity of the air and oil vapors assure combustion(flame) adjacent the opening in top wall I6 whenever oil vapors passtherethrough regardless of the quantity or speed of such vapors. Anyvapors in excess of that which will mix with the air present to producecombustion, pass on out of the combustion chamher to the chimney,without danger of causing an explosion in the apparatus. Thus applicanthas eliminated the possibility of explosion due to excess of oil vaporswithout adversely affecting the efliciency of his apparatus by utilizingan excess of air.

The complete operation of the apparatus shown and described is asfollows:

By suitable adjustment of valve 34, oil is admitted to burner l I. Theoil is ignited by a flame introduced into the apparatus through the door32 or by a. conventional form of pilot device.

Initially combustion occurs on the surface of the oil, the necessary airbeing supplied by primary air inlet openings 20. As soon as sumcientheat is developed the available oil is vaporized and At any rate, thezone of combustion does move farther upward and away from the oil as therate of vapor generation increases. of course, as soon as the zone ofcombustion is above anyof the primary air holes 20, the air enteringthrough those particular holes is being premixed with the oil vapors inadvance of combustion.

At all times after the initial lighting, there is suflicient' heatproduced by the flame to evaporate the oil introduced substantially asfast asit is admitted up to a predeterminable maximum.

when the burner is operating at or near this predetermined maximum rateof vaporization substantially all of the combustion (flame) is localizedabove the top wall 16, and substantially all of the air admitted throughprimary air inlet openings 20 is utilized for premixing, the airadmitted through secondary air inlet openings 2| serving to localize thelower limit of the zone of combustion adjacent the top wall It. Bysuitable regulation of valve 34 the lower limit of the zone ofcombustion may be fixed either immediately over the surface of the oil,above the top wall l6, or in an intermediate locality.

The scope of the invention is indicated in the appended claims.

I claim: v

1. Combustion apparatus comprising a burner of the vaporizing pot typehaving a tubular side wall provided with an integral radially outwardlyextending annular rib adjacent the top thereof, a plurality of air inletopenings formed in said rib, a centrally apertured top wall positionedwithin the burner below said air inlet openings, and a centrallyapertured baiile ring positioned above said rib, the opening in thebaflle ring being substantially larger than and arranged in alignmentwith the opening in the top wall, the baiiie ring and said air inletopenings being constructed and arranged so that the axes of said airinlet openings intersect the plane of the battle ring at a substantialangle, whereby the air admitted through said openings impinges againstthe bafilering.

2. Combustion apparatus as defined in claim 2, wherein the side wall ofthe burner is of frustoconical shape and the external rib is located inthe region of the greatest diameter of the side wall.

BEN mum. 25

of the above numbered patent requiring correctien as follows:

CERTIFICATE OF CORRECTION. V

November 21 1959 BEN VALJEAN.

It is hereby certified that error appears in the printed speeificationPage}, sec- Patent No]. 2,18 4l+5- 0nd column, line 19, Claim 2., for"claim 2," read c1aim1,-; and that the said Letters Patent should beread with this correction-therein'that the same may conformfd the recordof'the caee in'the Patent Office.

' Signed and sealed this 2nd day of January, A; D. 1919;

' Her 1m Vanhredale,

(Seel) Acting c onmissioner, of Patents.

